... advanced heat treatment,and all size of sucker rod available in grade C,D,KD,H, L,HY and This company is ... one of the main producers and providers of sucker rod in China, and get certificate of Authority to Use Office Monogram ... and became the firstfirm of passing "Dual Registration"by API in China. product gradeC,D,KD,H, L,HY and Polished ...